"First, the area of each candidate’s circle is proportional to their perceived likelihood of winning the nomination, according to the Intrade betting market. Mitt Romney’s circle is drawn many times the size of the one for the relatively obscure talk-radio host Herman Cain because Intrade rates Mr. Romney many times as likely to be nominated."

What makes Pawlenty so much more conservative than Daniels? What makes Huckabee more conservative than Pawlenty? Or Gingrich more conservative than Barbour? This looks like he made the background for the chart and then just threw darts with the candidates' names at it.